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FOM sem 1 > reproduction > Flashcards

reproduction Flashcards

1
Q

what are the functions of the male reproductive system

A

production of sperm cells
production of male sex hormones
sustaining and transfer of sperm cells into female

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2
Q

what are primary sex organs (in males)

A

gonads - site of gamete and hormone production
testes in males

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3
Q

what are secondary sex organs (in males)

A

structures essential in caring for and transporting sperm cells
ducts, accessory sex organs, penis in males

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4
Q

where is the scrotum located

A

extends from the body behind the penis

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5
Q

describe the structure of the scrotum

A

sac like > divided into two compartments (tunica vaginalis and tunica albuginea)
thin layer of smooth muscle within the dermis (dartos)
skeletal muscle under the dermis (cremaster)
rich blood and nerve supply

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6
Q

what are the functions of the scrotum

A

support and protect testes
help regulate temp of testes to maintain at around 35 degrees Celsius

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7
Q

where are the testes located

A

within the scrotum

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8
Q

describe the structure of the testes

A

oval shaped
~ 4-5 cm
each testis divided into 300-400 compartments called lobules
each lobule contains a long tube called a seminiferous tubule (where sperm is produced)

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9
Q

what are the functions of testes

A

production of sperm cells and sex hormones

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10
Q

why are the testes located externally to the body if it is such a vital organ

A

assists with strict temperature regulation of around 35 degrees

core temperature (37 degrees) is bad as it negatively impacts spermatogenesis and metabolism and increases the risk of testicular cancer

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11
Q

how is the temperature of testes maintained

A

located outside body - temp receptors and sweat glands in scrotum

cremaster muscle - contracts in the cold to bring testes closer to warm pelvis and relaxes in heat to bring testes away from warm pelvis

dartos muscle - contracts in the cold to increase wrinkles which decreases surface area for heat loss and vice versa in the heat

counter current heat exchange - network of testicular veins (pampiniform plexus) around tesituclar artery > heat transfer away from arterial blood to venous blood > maintains a cooler temperature in blood going to testes

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12
Q

what is the tunica vaginalis

A

a chamber of the scrotum that is lined by serous membrane to reduce friction

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13
Q

what is the tunica albuginea

A

a chamber in the scrotum that is deep to the tunica vaginalis and is a dense CT capsule

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14
Q

what are seminiferous tubules

A

highly coiled tubule in each lobule of testes

contains spermatogenic cells and sertoli cells

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15
Q

what are in-between the seminiferous tubules

A

blood vessels and leydig cells (make androgens ie testosterone)

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16
Q

what are sertoli cells

A

cells that extend from the basement membrane to the lumen of the seminiferous tubule and has tight junctions connecting adjacent cells to form the blood testis barrier

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17
Q

what is the function of the blood testis barrier

A

isolates spermatogenic cells from blood because the immune system recognises sperm foreign so the barrier prevents a self immune response

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18
Q

what are the functions of sertoli cells

A

control release and mvmt of sperm cells

nourish sperm cells

prevent self immune reaction (blood testis barrier)

secrete inhibin to slow down sperm production

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19
Q

what is spermatogenesis

A

process of production of sperm

begins in outermost layer of seminiferous tubule (basement membrane) and proceeds towards lumen

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20
Q

what are the three elements of spermatogenesis

A

mitotic proliferation

meiotic division

spermiogenesis

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21
Q

outline the process of spermatogenesis

A
  1. spermatogonia divide into more spermatogonia via mitosis
  2. spermatogonium moves away from basement membrane to form primary spermatocyte
  3. primary spermatocyte undergoes meiosis 1 to form secondary spermatocyte
  4. secondary spermatocyte undergoes meiosis 2 to form spermatid
  5. spermatid undergoes spermiogenesis to form sperm
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22
Q

what is spermiogenesis

A

final stage of spermatogenesis where the round spermatid turns into an elongated spermatozoa so that it is adapted for reaching and penetrating an oocyte

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23
Q

what are the 4 key stages of spermiogenesis

A
  1. development of acrosome - contains digestive enzymes to help penetrate oocyte
  2. development of flagellum - motility
  3. condensation of nucleus - protects DNA
  4. shedding of excess cytoplasm by sertoli cells - streamlined sperm for better motility
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24
Q

what are the three main parts of the sperm structure

A

head - contains compact nucleus covered by acrosome which has digestive enzymes for penetration of oocyte

mid-piece - connects head to the flagellum / has mitochondria to power motility

flagellum - tail used for motility

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25
Q

what are ducts in the testes responsible for

A

functional maturation, nourishment, storage and transport of sperm

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26
Q

what are the 5 main ducts involved w the testes

A

seminiferous tubules

rete testis - carry sperm from testes to efferent ducts

efferent ducts - connect rete testis to epididymis

epididymus

ductus (vas) deferens

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27
Q

describe the epididymus

A

posterior side of testis
7m long tubule
3 segments - head, body, tail

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28
Q

what are the 5 functions of the epididymus

A

monitors and adjusts composition of fluid produced by seminiferous tubules

recycle damaged sperm

stores and protects sperm

concentrates sperm

site of functional maturation of sperm

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29
Q

how does functional maturation of sperm occur

A

epididymus secretes a variety of proteins that bind to sperm > stabilise it so it can withstand force during ejaculation and trigger the flagellum to begin moving

dependent on androgens

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30
Q

describe the movement of sperm through the ductus deferens

A

tail of epididymus > ascends posterior side of testis > joins spermatic cord > ascends through inguinal canal into abdominal cavity > passes along later surface of bladder > approaches superior and posterior prostate gland > end enlarges to form ampulla of vas deferens > ejaculatory duct > seminal vesicle gland

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31
Q

what are the three parts of the urethra

A

prostatic - passes through prostate

membranous - through floor of pelvis, surrounded by EUS

spongy - through penis

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32
Q

what are the accessory glands

A

seminal vesicles
prostate gland
bulbourethral glands

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33
Q

what are seminal vesicles

A

paired pouch like glands attached to vas deferens near the base of the urinary bladder that secretes 60-70% of volume of semen

secretes alkaline fluid > neutralise acidic environment

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34
Q

what is the prostate gland

A

single donut shaped gland inferior to the bladder and surrounding the urethra that secretes a milky prostatic fluid that contributes 20-30% of the volume of semen

composed of a cluster of glands, each of which connect to prostatic ducts

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35
Q

what are bulbourethral glands

A

paired pea sized glands located at the base of the penis and connected to urethra which secretes a small amount of alkaline mucus into the urethra prior to ejaculation

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36
Q

what is semen

A

seminal fluid from accessory glands + sperm from testes = semen

sperm ~10% and seminal fluid ~90%

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37
Q

what are the key components of seminal vesicles

A

fructose - metabolised by sperm

prostaglandins - stimulate smooth muscle contractions

fibrinogen - coagulate semen > protect from acidic environments

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38
Q

what are the key substances of semen secreted by prostate gland

A

citric acid - ATP

proteolytic enzymes e.g fibrinolysin- break down clotting proteins > coagulate

seminalplasmin - antibiotic that prevents bacterial infections

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39
Q

Describe the structure of the penis

A

Root - internal in the body

Body - elongated / 3 cylindrical columns of erectile tissue > two large corpora cavernosa on the sides of penis and a single corpus spongiosum on the underside of the penis that surrounds urethra

Glans - end of penis that has high concentration of nerve endings / normally covered by foreskin

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40
Q

What are the functions of the penis

A

Deliver semen to the female during sexual intercourse

Transport urine out of the body

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41
Q

Outline how an erection occurs

A
  1. sexual stimulation
  2. Parasympathetic neurons release NO > dilation of arteries > increase blood flow
  3. Increase pressure in arterial blood > compress veins > reduced venous return
  4. Blood accumulates in vascular spaces within erectile tissue of penis
  5. Following orgasm > sympathetic nerves contract central artery and smooth muscle around erectile tissue > expels blood out of penis
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42
Q

Describe the production of testosterone

A

Produced by leydig cells in the testes
Increased during puberty > characteristic physical changes and initiate spermatogenesis

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43
Q

What are the functions of testosterone

A

Initiate and maintain spermatogenesis within the testes

Development of male secondary sexual characteristics and for maintaining sex drive

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44
Q

Outline the regulation of testosterone production

A
  1. hypothalamus initiates spermatogenesis by secreting GnRH which stimulates secretion of FSH and LH by anterior pituitary
  2. LH stimulate leydig cells > testosterone / FHS stimulate sertoli cells > androgen-binding protein > binds to androgen hormones e.g testosterone > become concentrated in seminiferous tubule > ensures testosterone levels remain high in testes
  3. Increased testosterone > initiate spermatogenesis but it also has negative feedback on GnRH production
  4. Sertoli cells respond to increase sperm levels by secreting inhibin > inhibits FSH secretion > negative feedback on cycle
  5. Circulating testosterone levels stimulate sex drive and develop secondary sexual characteristics
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45
Q

What is cryptorchidism

A

Failure of one or both testes to descend into scrotum > sterility due to higher temperatures in the pelvic cavity / increased risk of testicular cancer

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46
Q

What is erectile dysfunction

A

Consistent inability of an adult male to ejaculate or attain or hold an erection long enough for sexual intercourse

Often caused by insufficient release of NO

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47
Q

what are the functions of the female reproductive system

A

production of oocytes in the ovaries
production of female sex hormones (estrogen and progesterone)
reception of spermatozoa
nurturing the development of a new individual

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48
Q

what are the primary sex organs in the female reproductive system

A

gonads - ovaries

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49
Q

what are the secondary sex organs in the female reproductive system

A

uterine tubes, uterus, vagina, mammary glands

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50
Q

where are the ovaries located

A

upper pelvic cavity on the lateral sides of the uterus

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51
Q

what are the two ligaments supporting the position of the ovaries

A

suspensory ligament (contains ovarian vein and ovarian artery)

ovarian ligament

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52
Q

describe the structure of the ovaries

A

denser outer part known as cortex - contains ovarian follicles

inner looser part known as medulla - contains blood vessels and nerves

endocrine and exocrine gland

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53
Q

what are the functions of the ovaries

A

production of oocytes
production of female sex hormones

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54
Q

what is an ovarian follicle

A

oocyte surrounded by supporting granulosa cells

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55
Q

what are primordial follicles

A

primary oocyte + single layer of flat follicle cells

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56
Q

what are the two phases of the ovarian cycle

A

pre-ovulatory (follicular) phase - all events prior to ovulation

post-ovulatory (luteal) phase - all events after ovulation

57
Q

what are the two inter-related processes occurring in the ovarian cycle

A

oogenesis
folliculogenesis

58
Q

what is a primary follicle

A

primary oocyte + 1-2 layers of cuboidal follicle cells

59
Q

what is a secondary follicle

A

enlarged oocyte
additional layers of follicle cells
multiple, small fluid-filled spaces develop between follicle cells

60
Q

what are tertiary follicles

A

mature (Graafin) follicle
single, large fluid-filled space (antrum)
oocyte surrounded by specialised follicular cells called granulosa cells

61
Q

follicle cells secrete what

A

estrogen

62
Q

what is ovulation

A

release of oocyte from ovary
granulosa cells stay w released oocyte
oocyte enters uterine tube

63
Q

what is the corpus luteum

A

glandular structure left behind in ovary after ovulation
empty tertiary follicle collapses
remaining follicular cells proliferate to fill space

64
Q

corpus luteum secretes what

A

estrogen AND progesterone

65
Q

what is corpus albicans

A

if fertilisation doesn’t occur, corpus luteum degenerates into corpus albicans

composed of scar tissue

66
Q

what is folliculogenesis

A

development of follicle

67
Q

what is oogenesis

A

formation of oocytes

68
Q

outline the process of oogenesis

A
  1. oogonium undergoes mitosis to form millions more oogonium in ovaries (this process stops before birth)
  2. oogonium forms a primary oocyte (before birth)
  3. primary oocyte undergoes meiosis 1 when puberty begins to form secondary oocytes and polar bodies
  4. secondary oocyte undergoes meiosis 2 when fertilisation occurs
  5. secondary oocyte becomes a zygotes
69
Q

where are the uterine tubes located

A

connected to uterus and lies close to (but not connected to) ovary

70
Q

what are the 3 segments of the uterine tubes

A

infundibulum - has fimbriae which collect ovulated oocyte

ampulla - site of fertilisation

isthmus - site of sperm maturation

71
Q

what are the walls of the uterine tubes comprised of

A

ciliated columnar epithelium w mucous-secreting cells

72
Q

what is the function of the uterine tubes

A

transport oocytes from ovaries to the uterus

site of fertilisation (ampulla)

site of sperm maturation (isthmus)

73
Q

where is the uterus located

A

near the floor of the pelvic cavity anterior to the rectum and posterosuperior to the bladder

74
Q

what are the 3 regions of the uterus

A

fundus
body
cervix

75
Q

what are the 3 layers of the uterus wall

A

endometrium - innermost layer, highly vascularised / two layers (stratum functionalis and stratum basalis)

myometrium - thick layer of smooth muscle (contract during childbirth in response to oxytocin)

perimetrium - external layer composed of epithelium

76
Q

what are the functions of the uterus

A

provides mechanical protection, nutritional support and waste removal for developing embryo

contractions in muscular wall allows for ejection of foetus at birth

77
Q

describe the stratum functionalis

A

functional layer
grows during uterine cycle
sheds at menstruation

78
Q

describe the stratum basalis

A

basal layer
denser CT
permanent, does not shed
gives rise to new functionalis

79
Q

describe the cervix

A

contain mucous glands

mucous consistency varies during cycle (less viscous at ovulation to allow sperm passage)

80
Q

what are the 4 phases of the female reproductive cycle

A

menstrual phase (days 1-5)

follicular phase (estrogen from follicle cells)

ovulation

luteal phase (estrogen and progesterone from corpus luteum)

81
Q

where is the vagina located

A

extends from exterior of body to the uterine cervix

82
Q

describe the structure of the vagina

A

internal wall - stratified swamis epithelium that forms protective surface barrier

beneath this layer is a thin layer of CT containing vaginal glands that secrete lubricating mucous

beneath CT layer is a thick layer of smooth muscle

83
Q

what are the functions of the vagina

A

serves as a passageway for elimination of menstrual fluids

receives the penis during sexual intercourse and holds sperm prior to their passage into the uterus

forms the inferior portion of the birth canal through which the foetus passes during delivery

84
Q

what are the external female genitalia

A

vestibule
labia minora
clitoris
prepuce
labia majora
bartholin’s glands

85
Q

what is the vestibule

A

space into which vagina and urethra open

86
Q

what is the labia minora

A

small thin fold of skin that border the vestibule

87
Q

what is the clitoris

A

small rounded tissue project that contains two erectile structures called corpus cavernosa

88
Q

what is the prepuce

A

extensions of the labia minora that encircle the clitoris

89
Q

what is the labia majora

A

prominent skin folds that encircle and partially conceal the labia minora

90
Q

what are bartholin’s glands

A

secrete lubricating mucus into the vestibule

91
Q

what 3 things are involved in the ovarian cycle of the female reproductive cycle

A

follicular phase
ovulation
luteal phase

92
Q

what 3 things are involved in the uterine cycle of the female reproductive cycle

A

menstrual phase
proliferative phase
secretory phase

93
Q

what happens during the pre ovulation phase

A

GnRH > FSH > development of follicles > secrete estrogen which thicken the stratum functionalis

94
Q

what happens during ovulation

A

LH surge triggers ovulation

95
Q

what happens during the post ovulatory phase

A

corpus luteum forms which secretes oestrogen and progesterone, but the negative feedback of the production of these hormones is suppressed for ~ 10 days

96
Q

what happens during the menstrual phase

A

negative feedback of GnRH begins after ~ 10 days > no oestrogen or progesterone > formation of corpus albicans as spiral arteries constrict > menstruation

97
Q

how does the contraceptive pill work

A

contains oestrogen and progesterone > triggers negative feedback > decrease GnRH > no FSH and LH > decrease growth of follicles > no ovulation > decrease chance of pregnancy

98
Q

what happens if fertilisation and implantation occurs

A

embryo secretes hCG hormone which mimics LH, which keeps corpus luteum alive until placenta develops > secretion of progesterone and estrogen so that menstruation doesnt occur

99
Q

what are ovarian cysts

A

fluid filled sac in or on the ovary - usually non cancerous

cancerous cysts - more likely in women >40

can cause pain, pressure, dull ache, feeling of fullness in the abdomen, pain during sex, vaginal bleeding

usually require no treatment but cysts more than 5cm may need surgery

100
Q

what is endometriosis

A

characterised by growth of endometrial tissue outside the uterus > enters the pelvic cavity (ovaries, outer surface of uterus, sigmoid colon, cervix, abdominal wall, bladder) > breaks down and bleeds > inflammation, pain and scarring

101
Q

Why are hundreds of millions of sperm released into the vagina

A

Many of the sperm die due to the acidic nature of the vagina

102
Q

What makes passage of sperm easier in the cervix

A

If the cervical mucous is watery (pre ovulation)

103
Q

What in the uterus aids the movement of sperm away from the cervix and towards the uterine tubes

A

Uterine myometrium

104
Q

What happens to sperm in the uterine tubes

A

Sperm’s flagella becomes hyperactive to generate enough force to push through protective layers around oocyte

Plasma membrane above the sperm’s acrosome thins so that it permits the release of acrosomal enzymes

105
Q

Outline the process of fertilisation

A
  1. Hundreds of sperm attracted to corona radiata > begin breaking through barrier of granulosa cells
  2. Contact w zona pellucidia triggers acrosome reaction > secrete digestive enzymes that breakdown glycoprotein membrane of zona pellucia and help expose oocyte’s plasma membrane
  3. Single sperm succeeds in burrowing through corona radiata and zona pellucida and making contact w oocyte’s plasma membrane > sperm’s plasma membrane fuses w oocyte plasma membrane > sperm releases nucleus into cytoplasm of oocyte
106
Q

Describe IVF

A

used when woman may have blocked or compromised uterine tubes

Used when man may have low sperm count or abnormal or immotile sperm

Involves mixing sperm and oocytes together in a Petri dish, then transferring zygotes into the uterus

Rate of success of IVF correlated w a woman’s age

107
Q

what are the 3 parts of the prenatal period and length of each

A

fertilisation - 2nd week

embryonic period - 2nd-8th week

fetal period - 8th week to birth

108
Q

what is clinical age

A

using the date of mother’s last period to calculate the unborn child’s age

109
Q

what is developmental age

A

unborn child’s age from fertilisation

14 days less than clinical age as fertilisation occurs ~14 days after last period

110
Q

outline preimplantation development

A

day 0 - zygote forms as fertilisation is complete

day 1-3 - zygote undergoes mitosis (cleavage) making the zygote go from 2 cell to 4 cell to 8 cell and so on

day 4 - morula (solid ball of cells) form > begins to descend towards uterus from oviduct

day 5 - morula continues to proliferate and differentiate into blastocyst

day 6-7 - trophoblast cells release enzyme > break down zona pellucida > blastocyst contacts and adheres to uterine lining

111
Q

outline implantation

A

day 8

trophoblast cells divide into several layers

cells near endometrial wall (synctiotrophoblast) develops into cords that hold onto endometrium

inner and outer layer of trophoblast cells form chorion > secrete hCG

112
Q

what is human chorionic gonadotropin

A

hCG

transported in bloodstream from uterus to ovary

in ovary, it directs corpus luteum to remain alive and continue secreting estrogen and progesterone which prevents menstruation

levels peak around 8-9weeks after fertilisation and then declines after this as placenta secretes estrogen and progesterone to prevent menstruation

113
Q

what is the epiblast

A

upper layer of embryonic disc that will become embryo layers

114
Q

what is the hypoblast

A

lower layer of embryonic disc that will become extra embryonic tissue including yolk sac

115
Q

what is the primitive streak

A

midline region of the embryonic disk thickens in early week 3

beginning of gastrulation

116
Q

what is gastrulation

A

epiblast cells migrate through the primitive streak to become 3 germ layers

early migrating cells displace hypoblast cells to form embryonic endotherm

later migrating cells form the mesoderm

this embryonic development progresses from the cranial end, later caudal

117
Q

what are the 3 germ layers

A

ectoderm
mesoderm
endoderm

118
Q

what does the ectoderm produce

A

skin, nervous system, skull, enamel, inner ear, adrenal medulla, eye, ear

119
Q

what does the mesoderm produce

A

muscle, some viscera, bones, blood, lymph

120
Q

what does the endoderm produce

A

epithelial lining of ducts and organs, some viscera, primordial germ cells

121
Q

outline development of the neural tube

A

mesoderm cells develop into notochord which induces the overlying ectoderm to form the neural plate > gives rise to CNS

groove in the neural plate at day 18 > become larger > fuse > produce neural tube

122
Q

outline the development of neural crest cells

A

develop from neuroectodermal cells along inner margins of neural tube

will later produce ganglia in spine and ANS

123
Q

what are teratogens

A

factors that cause birth defects

e.g alcohol, thalidomide, maternal-fetal infections

124
Q

what are NTDs

A

neural tube defects

occurs due to the failure of fusion of grooves in the neural plate which from neural tubes

125
Q

What are the major functions of the placenta

A

Nutrient, gas, waste exchange

Hormone production

Protection from environment

Immune protection

126
Q

What are the important placental hormones

A

Human chorionic gonadotropin

Progesterone and estrogen

Placental lactogen and GH

Relaxin

127
Q

What is the function of progesterone made by the placenta

A

Relaxes uterine muscle to prevent labour

Induces breast changes in preparation for lactation

128
Q

What are the functions of placental lactogen and GH

A

Induce maternal metabolic changes e.g insulin resistance > maintains maternal placental glucose concentration to compensate for placental uptake

Promote breast changes in prep for lactation

129
Q

What are the functions of relaxin released by the placenta

A

Vascular - vasodilation and decreased myogenic tone

Cardiac - increase Q and increase SV

Renal - increase GFR

Joints and cartilage - increase flexibility + cervical softening

130
Q

How does the placenta act to protect the fetus from the external environment

A

Barrier to many bacteria but many viruses can still cross the placenta

Drug and hormone metabolism and clearance e.g deactivation of cortisol to cortisone

Does not block alcohol tho as it can diffuse across membrane

131
Q

How does the placenta aid immunity

A

IgG antibodies are transferred across the human placenta (esp in late preggo) > maternal immunisation can protect newborn against disease

132
Q

Outline increased beta cell mass during pregnancy

A

Happens in early pregnancy

Increased insulin secretion > promotes fat storage

133
Q

Outline altered glucose metabolism in late pregnancy

A

Adaptations maintain maternal circulating glucose to maintain fetal supply > increase insulin but decrease insulin sensitivity and increase basal hepatic glucose production via gluconeogenesis

134
Q

Outline lipid metabolism during pregnancy

A

Decrease in the first 8 weeks and then increase

Late preg > increase insulin resistance > increase lipolysis > increase circulating FA and glycerol for maternal and placental energy supply

Shift to fat oxidation as maternal energy source

Increase cholesterol > placental steroid synthesis

Fasting > increase fat oxidation > ketones for fetal energy

135
Q

What are the cardiovascular adaptations during pregnancy

A

Increase HR, increase SV, increase Q

Decrease BP first half of pregnancy

Increased blood volume

136
Q

Why is there an increase in cardiac function during pregnancy

A

Q increased bc blood volume increases

Progesterone may stimulate maternal heart growth

Elevated estrogen in late pregnancy may allow increased activation of stretch activated kinases to further stimulate heart growth

137
Q

Why does BP fall in the first half of pregnancy

A

Vascular resistance decrease + arterial compliance increase > increase blood vessel volume and decrease after load on heart

Vasodilation and arterial compliance due to increase NO production (elevated maternal relaxin and estrogen)

138
Q

Why is there an increase in blood volume during pregnancy

A

Elevated aldosterone and cortisol (esp late pregnancy) > sodium and water retention > increase fluid volume

RAAS upregulated by estrogen (esp late preg) > increase sodium absorption

Osmostat set point changes so that thirst increases at lower than usual osmolality

139
Q

Are there clinical consequences to increased fluid volumes during pregnancy

A

Development of oedema

Increase CT fluid can also increase laxity and pain of some joints

FOM sem 1 (10 decks)

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